Place a bubble level onto one of the vertical rails on the vertical arm. The level should be oriented as in the picture below:

Bubble Level On Vertical Rail

Move the vertical arm to a position where it is directly above one of the four platform support legs.

Position 1 - Overhead View

Check for level at this position. Adjust the brass foot under the arm to attain a level reading on the bubble level. If this side is too low, extend the foot to raise this side. If this side is too high, retract the foot into the leg to lower this side, then extend the opposite foot to balance the platform.

Move the vertical arm to a position directly above the opposite leg.

Position 2 - Overhead View

Check for level at this position. Adjust the brass foot under the arm to attain a level reading on the bubble level. If this side is too low, extend the foot to raise this side. If this side is too high, retract the foot into the leg to lower this side, then extend the opposite foot to balance the platform.

Move the vertical arm to a position directly above either of the remaining legs.

Position 3 - Overhead View

Check for level at this position. Adjust the brass foot at this position to attain a level reading on the bubble level. If this side is too low, extend the foot to raise this side. If this side is too high, retract the foot into the leg to lower this side, then extend the opposite foot to balance the platform.

Move the vertical arm to the opposite leg, then position the vertical arm directly above this leg.

Position 4 - Overhead View

Check for level at this position. Adjust the brass foot at this position to attain a level reading on the bubble level. If this side is too low, extend the foot to raise this side. If this side is too high, retract the foot into the leg to lower this side, then extend the opposite foot to balance the platform.

Using your fingers, verify that each foot is securely in contact with the floor. If necessary, adjust each foot so that it makes firm contact.

Repeat this procedure to ensure that the platform is level at each leg and that each foot is firmly in contact with the floor.